RE: Re: HYB: Germination!!! - complexities

You know. there has long been an old wives tale that if you put the pot with
the germinating seedlings close to the ones that aren't germinating it will
encourage germination.  Wonder if that was due to the ethylene gas?  Also,
the burrito method of placing the seeds in baggies may work better due to
the ethylene gas being trapped in the baggy?

Dana Brown
Region 17 Judges Training Chairperson
AIS, MIS, ASI, RIS, TBIS
MALEVIL IRIS GARDENS
Lubbock, TX
Zone 7 USDA, Zone 10 Sunset
 <d*@malevil-iris.com>


-----Original Message-----
From: Linda Mann [l*@volfirst.net]
Sent: Wednesday, November 06, 2002 7:10 AM
To: iris-talk@yahoogroups.com
Subject: [iris-talk] Re: HYB: Germination!!! - complexities


I took one class in horticulture in the ancient past - Plant
Propagation, of all things....

In these two weighty tomes on seed germination, it does mention ethylene
....
...p372-373. vol 1...
...a decrease in vigor has been considered an invitable and irreversible
part of seed handling and aging.  However, Takayanagi and Harrington
(1971) have reported that application of exogenous ethylene can
accelerate the germination of aged seeds, thus suggesting that at least
a partial revival in vigor is possible.......[some researchers have
found different results]..such discrepances may have resulted from
differences in vigor of the seed lots used. [not to mention among
species I bet!]
............
p 67, Vol II...
"Recent studies .....[of imbibed clover seeds] produce ethylene
..[and].. carbon dioxide, and their germination is enhanced by
both...the self-regulatory activity of gases which are produced by the
seeds may ...[favor] germination in the soil, where concentrations [of
gases may increase next to the seeds because the gases can't easily
diffuse away].  [& they think this may be true of other species]
........................

They review a <lot> of literature about experiments with a lot of kinds
of plants in which they found a lot of variability in particular species
(not irises, mostly annuals, crop plants, but also some perennial
ornamentals) of germination responses depending on interactions during
bloom, seed set, ripening, storage, stratification, and planting of
temperature, light, gases (CO2 & oxygen), nitrogen, organic compounds,
moisture/humidity, soaking, etc etc.  Lots of enzymatic reactions going
in various directions, some producing germination inhibitors, some
enhancers, some reactions are one way, others are reversible, some are
time dependent (once the reaction reaches a certain point, it keeps
going) -

Throw on top of that the genetic variability of TBs (and other beardeds
for that matter) and who knows -  maybe ethylene in Dana's fridge with
her crosses enhanced germination and in mine it might send them into
permanent dormancy!  Just kidding, that's not likely, but certainly
another potential source of variability.

Hope that helps ?????

Jim asked:
<Can some of our
                       horticulturally-trained comment on ethylene gas
from the apples and
                       seed storage? ....How about damp iris seeds with
the
                       apples in the refrigerator?>

--
Linda Mann east Tennessee USA zone 7/8

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